The third layer in The Internet Protocol Stack responsible for routing Datagrams across multiple networks via the most optimal route.
It can be divided into two planes:
Data Plane: The per-Router functions that determines how a Datagram arriving at a router’s input link gets forwarded to one of the router’s output links.Control Plane: The network-wide logic that controls how a Datagram is routed among routers along an end-to-end path from source Host to destination host, e.g. routing algorithms and protocols.